title: Reversal of facial selectivity in a thia-Claisen rearrangement by incorporation of a vinylic bromine substituent.
abstract: Thia-Claisen rearrangements have been carried out using N-benzylpyrrolidine-2-thione and chiral allylic bromides derived from D-mannitol. Introduction of a bromine atom onto the double bond of the allylic bromide reverses the sense of diastereoselectivity in the [3,3]-sigmatropic rearrangement. Density functional theory calculations lead us to rationalise the observed selectivity in terms of a Cíeplak effect.
authors.affiliation: Department of Chemistry, University College London, Christopher Ingold Building, 20 Gordon Street, London, WC1H 0AJ, UK. m.j.porter@ucl.ac.uk.
authors.forename: Adam R
authors.initials: AR
authors.lastname: Ellwood
authors.forename: Anne J Price
authors.initials: AJ
authors.lastname: Mortimer
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Goodman
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Porter